Night vision devices are widely used in the military to provide soldiers, aviators and sailors with the ability to view objects at night or during other low light conditions. As a result, many night vision devices are currently being manufactured according to exacting military specifications and designs. Similarly, many such night vision devices are being manufactured for specific military applications such as part of the sights of various weapons or as part of goggle assemblies that attach to an aviator's or soldier's helmet. As a consequence, many of the night vision devices currently being manufactured are neither affordable nor easily adapted to non-military uses by the general public.
Night vision devices typically include an image intensifier tube that converts low intensity and/or infrared energy into visible light. Such night vision devices typically require sophisticated power supplies and circuitry to control the operation of the image intensifier tube and sophisticated optical arrangements that direct the infrared energy into the image intensifier tube and visible light away from the image intensifier tube. In military applications, the various military personnel are trained in how to use and adjust the night vision devices they are issued. However, a night vision device designed for use by the general public must have simple adjustments that can be readily operated by a variety of different users in a dark environment. Preferably, a night vision device designed for the general public would have little or no adjustments so that a person need only turn on the device and look through it to obtain night vision.
As military sales wain, more and more night vision devices are being marketed directly to the general public. However, few of such prior art night vision devices are designed to be both low cost and easy to operate. ITT Corporation, the assignee herein, manufactures a variety of night vision devices for the military and the general public. Examples of some of the handheld monocular devices that are being sold to the public are shown in U.S. patent application Ser. No. 08/108,989 entitled NIGHT VISION BINOCULARS, filed Aug. 18, 1993, now U.S. Pat. No. 5,495,364, and U.S. patent application Ser. No. 08/405,172 entitled COMPACT NIGHT VISION DEVICE, filed Mar. 16, 1995. Such prior art monocular devices are far easier to use and are much less expensive than are their military counterparts. However, even these night vision devices have adjustable objective lens assemblies and folded optics that add significantly to the overall cost of the night vision device.
It is therefore an object of the present invention to provide a night vision monocular device with a simplified optical arrangement, thereby making the night vision monocular both easier to use and less expensive to manufacture.
It is a further object of the present invention to provide a housing for a night vision monocular device that is low cost and easily assembled with the simplified optical arrangements contained within the night vision monocular device.